One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,6,7)(3,4,8,5)(9,10,13,14)(11,15,19,17)(12,20,21,16)(18,23,24,22)(25,26,30,35)(27,31,38,32)(28,33,34,29)(36,37,39,40)(1,3)(2,5)(4,7)(6,8)(9,10)(11,17)(12,16)(13,14)(15,19)(18,23)(20,21)(22,24)(25,27)(26,31)(28,39)(29,37)(30,38)(32,35)(33,40)(34,36) involution — undirected(1,4,6,5)(2,3,7,8)(10,14)(15,17)(16,20)(22,23)(25,27,30,38)(26,32,35,31)(28,36,34,39)(29,37,33,40)(1,3)(2,4)(5,7)(6,8)(9,10)(11,15)(12,16)(13,14)(17,19)(18,22)(20,21)(23,24)(25,27)(26,32)(28,36)(29,37)(30,38)(31,35)(33,40)(34,39) involution — undirected(1,5,6,4)(2,3,7,8)(9,11)(10,15)(12,18)(13,19)(14,17)(16,22)(20,23)(21,24)(25,28)(26,33)(27,36)(29,35)(30,34)(31,37)(32,40)(38,39)(1,3)(2,5)(4,7)(6,8)(9,12)(10,16)(11,18)(13,21)(14,20)(15,22)(17,23)(19,24)(25,29,30,33)(26,34,35,28)(27,37,38,40)(31,36,32,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.