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