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