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