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