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