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