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