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