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