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