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