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