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