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