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