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