One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,6,7)(3,4,8,5)(9,10,15,13)(11,16,19,21)(12,17,23,22)(14,18,24,20)(25,26,30,35)(27,31,38,32)(28,33,34,29)(36,37,39,40)(1,3)(2,5)(4,7)(6,8)(9,11,15,19)(10,16,13,21)(12,20,23,18)(14,22,24,17)(25,27)(26,31)(28,39)(29,37)(30,38)(32,35)(33,40)(34,36)(1,4,6,5)(2,3,7,8)(11,19)(12,23)(16,21)(17,22)(25,27,30,38)(26,32,35,31)(28,36,34,39)(29,37,33,40)(2,7)(4,5)(9,12)(10,17)(11,20)(13,22)(14,16)(15,23)(18,19)(21,24)(25,27)(26,31)(28,39)(29,37)(30,38)(32,35)(33,40)(34,36) involution — undirected(1,5,6,4)(2,3,7,8)(9,13,15,10)(11,21,19,16)(12,17,23,22)(14,18,24,20)(25,28)(26,33)(27,36)(29,35)(30,34)(31,37)(32,40)(38,39)(1,3)(2,5)(4,7)(6,8)(9,14)(10,18)(11,22)(12,16)(13,20)(15,24)(17,19)(21,23)(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.