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