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