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