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