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