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