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