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