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