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