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