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