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