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