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