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