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