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