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