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