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