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