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