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