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