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