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)(26,30)(27,34)(28,37)(31,39)(32,33)(35,38)(9,11,13,18)(10,14,17,15)(12,21,22,19)(16,24,20,23)(25,26)(27,35)(28,32)(29,33)(30,37)(31,34)(36,38)(39,40)(1,3,5,4)(2,6,7,8)(9,11)(10,15)(12,19)(13,18)(14,17)(16,24)(20,23)(21,22)(25,27)(26,31)(28,36)(29,34)(30,38)(32,39)(33,35)(37,40)(1,4,5,3)(2,6,7,8)(11,18)(14,15)(19,21)(23,24)(26,32)(27,34)(28,37)(30,33)(31,38)(35,39)(9,12,13,22)(10,16,17,20)(11,19,18,21)(14,23,15,24)(26,33)(27,34)(30,32)(36,40)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.